I have this same question regarding the Netflix Dolby Vision so thanks for posting. We have the ARRIS XG1v4 set top box, which we have had for about 20 months now. (there are many forums out there that detail several issues that Comcast has failed to resolve but it 'mostly' 'works'). Which set top box do you use?
the HDR10 is open source (no paid license needed).
So does anyone at Comcast/Xfinity care to address this? It appears either no one knows or no one cares. Please show some interest and help.